Katie Bryan, 43, racked up the charges for downloading the "best of Neil Diamond" album on iTunes. Orange, her mobile provider, charges £8 per MB for data roaming, meaning her approximately 326MB album (priced at £8.99) ended up costing her £2,609.31.

Fortunately for Miss Bryan, Orange agreed to retrospectively sell her a £400 data bundle, reducing the bill by £2,209.31.

Here we outline which mobile operators charge the most for data roaming, as well as overseas voice calls and text messages.

As the table below demonstrates, Orange is among the costlier operators, charging £8 per MB in all destinations outside the EU, although these fees can be reduced by purchasing data bundles before you travel. O2 is slightly better, at £6 per MB.

Three is among the best operators when it comes to data roaming charges. It recently scrapped roaming fees for visitors to the US, as well as Indonesia, Sri Lanka and Macau, as part of its "Feel at Home" service. Six other countries – Australia, Italy, Austria, Sweden, Denmark and the Republic of Ireland – and the Chinese city of Hong Kong are already covered by the scheme, available to all customers.

EE offers good deals to some destinations, such as South Africa (where the cost of downloading a Neil Diamond album would "only" be £32.60) and Australia (£3 for 20MB - or 15p per MB), but is less cost effective when it comes to Japan and Brazil (both £50 for 10MB).

It could've been worse...

Miss Bryan purchased The Best of Neil Diamond (running time 75 mins, total data 326MBs). Had she downloaded the debut album by Welsh band Quiet Marauder, which contains 111 tracks with a total running time of four hours, 49 minutes, her bill would've been heftier. Assuming the two albums had the same sound quality - the download would've cost her £10,034.08 with Orange.

Five other albums you wouldn't want to download abroad

Album

Running time

Estimated download cost from South Africa*

Mike Oldfield's Light and Shade

82 minutes

£2,853.60

Miles Davis's Witches Brew

94 minutes

£3,271.20

Pink Floyd's The Wall

95 minutes

£3,306

George Harrison's All Things Must Pass

105 minutes

£3,654

Led Zeppelin live at the BBC

138 minutes

£4,802

*Calculations presume the same recording quality as the Neil Diamond album, and being it downloaded using Orange (cheaper bundles can be purchased).

Within the EU, data roaming charges are capped. Mobile firms cannot charge more than 24.5 pence for voice calls, 8.1 pence for text messages and 46 pence per MB for data usage. Costs can be further reduced by buying a data bundle. The Vodafone Euro Traveller package, for example, means that for £3 per day, you can use your regular tariff’s call, text and data allowances while abroad. In July the caps on data roaming charges within the EU will fall further, while last year four of the country's major mobile operators (EE, Three, Vodafone and Virgin Media) signed an agreement with the Government pledging their support to scrapping all mobile roaming charges by 2016.

Data roaming*

US

South Africa

Japan

Australia

Brazil

EU

O2

£6 per MB

£6

£6

£6

£6

46p

Three

10p

£3

£3

10p

£6

45.8p

Vodafone

£3

£3

£3

£3

£3

45.9p

EE

£3 for 20MB add-on (minimum spend required to use internet)

£10 for 10MB

£50 for 10MB

£3 for 20MB

£50 for 10MB

£1 for 20MB

Orange

£8

£8

£8

£8

£8

45.9p

T-Mobile

£3 for 20MB (minimum spend required to use internet)

£10 for 3MB

£25 for 3MB

£3 for 20MB

£25 for 3MB

£1 for 20MB

*Data roaming bundles are available for some networks that reduce the cost per MB

When it comes to voice calls and text messages, Three also offers some of the best deals, with calls from US to Britain costing just 20p per minute, and text messages just 7p.